This invention is directed to elastomeric adhesive compositions which significantly improve decay and adhesion properties of elastomeric laminates.
Personal care garments often include elasticized portions to create a gasket-like fit around certain openings, such as waist openings and leg openings. Laminates made from conventional elastic strands and elastic attachment adhesive are often used to create such elasticized portions. However, such laminates can be rough and uncomfortable. Furthermore, such laminates may cause red-marking on a wearer's skin if the fit is too tight and may result in leakage from the garment if the fit is too loose.
Elastomeric adhesive compositions are multifunctional in the sense that they function as an elastomer in a nonwoven composite while also serving as a hot melt adhesive for bonding substrates. Elastomeric adhesive compositions in the form of elastomeric adhesive films are currently recognized as suitable for use in the manufacture of personal care articles. More particularly, elastomeric adhesive compositions can be used to bond facing materials, such as spunbond, to one another while simultaneously elasticizing the resulting laminate. The resulting laminate can be used to form an elastomeric portion of an absorbent article, such as a region surrounding a waist opening and/or a leg opening.
One drawback of current elastomeric adhesive compositions is that the compositions lose their adhesiveness when the compositions are stretched and then bonded between two nonwoven substrates. Another drawback of current elastomeric adhesive compositions is that the elasticity of the compositions (in terms of tension decay) is negatively affected when laminates including the compositions are aged at elevated temperatures, for example around 130 degrees Fahrenheit, which is commonly experienced under hot boxcar storage conditions.
It appears that the poor tension and adhesion of the current elastomeric adhesive compositions results from the chosen base polymer, tackifier, and plasticizer chemistries as well as the unbalanced ratio of polymer to low molecular weight species in the formulation.
There is a need or desire for an elastomeric adhesive composition that can be used to create elasticized portions of a personal care garment, wherein the composition does not result in high tension decay or delamination when used to produce elastic nonwoven laminates.